Heater assembly for hair care appliance

Abstract

A heater assembly for a hair care appliance is described. The heater assembly includes: first and second frames arranged along a curved path to define an airflow path; a first resistive strip is supported by the first frame such that the first resistive strip is retained within the airflow path, and a second resistive strip is supported by the second frame such that the second resistive strip is retained within the airflow path.

Description

Technical Field

[0001] The present invention relates to a heater assembly for a hair care appliance. Background Art

[0002] The hair care appliance can utilize an airflow generator to generate an airflow through the hair care appliance, and utilize a heater assembly to heat the airflow so that the heated airflow can be emitted from the hair care appliance. A user of the hair care appliance can use the heated airflow to style hair. Summary of the invention

[0003] A first aspect of the present invention provides a heater assembly for a hair care appliance, the heater assembly comprising: first and second frames arranged along a curved path to define an airflow path; a first resistor bar supported by the first frame so that the first resistor bar is retained within the airflow path; and a second resistor bar supported by the second frame so that the second resistor bar is retained within the airflow path.

[0004] Arranging the frame, and thereby the resistor strip, along a curved path may enable a hair care appliance incorporating a heater assembly to have good ergonomics and a relatively compact arrangement. Specifically, it is ergonomically advantageous for the hair care appliance to include an inlet and a handle in which a relatively heavy component (e.g., an airflow generator) is located, and to include a curved portion of a rotating airflow path such that airflow enters via the inlet and is discharged from the outlet in a direction orthogonal to the longitudinal axis of the handle. By arranging the frame and the resistor strip along a curved path, the heater assembly may be located within the curved portion, thereby providing a relatively compact and ergonomic arrangement.

[0005] Providing two resistor bars can enable greater flexibility in the design of the heater assembly, which can improve the functionality of the heater assembly. For example, each resistor bar can have a different geometry, so that the geometry of each resistor bar can be tailored to a specific airflow pattern at a different point along the tortuous path. In another example, the geometry of each resistor bar can be modified so that each resistor bar operates at a different temperature, which can reduce the likelihood of the resistor bar overheating and failure.

[0006] Furthermore, having two resistor bars and two associated frames may enable each frame and resistor bar to be formed separately and positioned independently along a curved path. This may make the heater assembly easier to manufacture than, for example, an integral curved frame and integral resistor bar.

[0007] In use, an airflow may be generated through the heater assembly and along the airflow path. The first and second resistive strips may heat the airflow. Thus, in the context of the present invention, upstream and downstream may be defined relative to the airflow through the heater assembly.

[0008] The first and second frames may define at least a portion of an airflow path.

[0009] The first resistor bar can be defined between the cutouts in the first sheet, and the cutouts can define an airflow path. The second resistor bar can be defined between the cutouts in the second sheet, and the airflow path can extend through the cutouts in the second sheet. For example, forming the resistor bar from a sheet can enable better control of the geometry of the resistor bar than can be achieved using wires. Better control of the geometry of the resistor bar can enable improved functionality of the heater assembly. For example, the geometry of the resistor bar can be designed to smooth the airflow, or to provide different amounts of heat at different locations along a curved path. Similarly, the resistor bar can be designed to incorporate protrusions that protrude into the frame to support the resistor bar. These protrusions can replace a separate support structure that is more complex to manufacture and more obstructive to airflow. The cutouts can be formed by etching or stamping.

[0010] The first frame may be spaced apart from the second frame along a curved path. Providing separate spaced apart frames may improve the manufacturability of the heater assembly. Specifically, manufacturing two frames (each supporting a resistive strip, and then arranging the frames along a curved path) may be simpler than manufacturing a single curved frame supporting multiple strips. The first and second frames may be separate components.

[0011] The first frame may be spaced apart from the second frame by a spacer. Providing a spacer may increase the likelihood of achieving the desired spacing while also improving the ease of assembly of the heater assembly.

[0012] The spacer may define an airflow path. As a result, airflow through the heater assembly may be constrained to an intended flow path by the spacer and the frame. The spacer may include holes that define the airflow path.

[0013] The first and second frames may each include an aperture defining an airflow path; the curved path may extend through a center point of each aperture; and a portion of the curved path extending between the center points of each aperture may subtend a central angle of no greater than 100 degrees. As a result, a relatively good ergonomic arrangement may be provided for the hair care appliance compared to an angle of greater than 100 degrees.

[0014] The first and second frames may each include a hole defining an airflow path, and the first frame may include an upstream face and a downstream face. The first plane may extend between the upstream face and the downstream face and be perpendicular to the upstream face and the downstream face, and may extend through the center point of the hole of the first frame. A portion of the first resistor bar may be shaped so that when viewed in the first plane, the portion of the first resistor bar has a curved profile with a radius of curvature not greater than 45 mm. In use, the resistor bar may deflect due to the force of the airflow on the resistor bar and the temperature change of the resistor bar. The deflection may cause adjacent resistor bars to contact and short-circuit each other, which may cause the heater assembly to malfunction. Therefore, by having a curved profile, the deflection can be controlled by forming the resistor bar so that the resistor bar deflects in a known direction. This deflection control can improve the reliability and safety of the heater assembly by reducing the possibility of the resistor bars contacting and short-circuiting each other. Having a radius of curvature not greater than 45 mm can provide sufficient deflection direction control for the resistor bar to be positioned relatively close together, which can improve the compactness of the heater assembly compared to a heater assembly having a resistor bar having a larger radius of curvature.

[0015] The second plane may extend between and perpendicular to the upstream face of the first frame and the downstream face of the first frame, may extend perpendicular to the first plane, and may extend through the center point of the hole of the first frame. The portion of the first resistor bar may be shaped so that when viewed in the second plane, the portion of the first resistor bar has a curved profile. Thus, the portion of the first resistor bar may have a dome shape. When viewed in the second plane, the portion of the first resistor bar may have a curved profile with a radius of curvature not greater than 45 mm.

[0016] The second frame may include an upstream face and a downstream face. The third plane may extend between and perpendicular to the upstream face of the second frame and the downstream face of the second frame, and may extend through the center point of the hole of the second frame. A portion of the second resistor strip may be shaped such that when viewed in the third plane, the portion of the second resistor strip has a curved profile with a radius of curvature not greater than 45 mm.

[0017] The fourth plane may extend between and perpendicular to the upstream face of the second frame and the downstream face of the second frame, may extend perpendicular to the third plane, and may extend through the center point of the hole of the second frame. The portion of the second resistor strip may be shaped so that when viewed in the fourth plane, the portion of the second resistor strip has a curved profile. When viewed in the fourth plane, the portion of the second resistor strip may have a curved profile with a radius of curvature not greater than 45 mm.

[0018] The apex of the portion of the first resistor strip may be located no further downstream than the downstream face of the first frame, and the apex of the portion of the first resistor strip may be located no further upstream than the upstream face of the first frame. As a result, since the first resistor strip may be protected by the first frame, the possibility of the first resistor strip being damaged during handling, such as during assembly, may be reduced.

[0019] The apex of the portion of the second resistor line may be located no further downstream than the downstream face of the second frame, and the apex of the portion of the second resistor line may be located no further upstream than the upstream face of the second frame.

[0020] The apex of the portion of the first resistor bar may be located further downstream than the point at which the first resistor bar is held by the first frame. This may help provide relatively smooth airflow through the first resistor bar.

[0021] The apex of the portion of the second resistor strip may be located further downstream than a point at which the second resistor strip is held by the second frame.

[0022] The vertex of the portion of the first resistor strip may be centered at the center point of the hole of the first frame. Thus, better control of the deflection of the segment of the first resistor strip may be provided, as a greater magnitude of deflection may be expected towards the center point of the first resistor strip. The vertex of the portion of the second resistor strip may be centered at the center point of the hole of the second frame.

[0023] The heater assembly may include a first group and a second group. The first group may include a first plurality of resistor bars including a first resistor bar, and the second group may include a second plurality of resistor bars including a second resistor bar. The first plurality of resistor bars may be electrically connected in series with each other, and the second plurality of resistor bars may be electrically connected in series with each other. Arranging the resistor bars into groups and connecting the resistor bars within the groups in series may reduce the amount of wiring of the heater assembly and simplify the wiring compared to the arrangement of individual resistor bars connected in parallel. This may reduce costs and improve the manufacturability of the heater assembly.

[0024] The first group may include a first temperature sensor for sensing the temperature of the first group, and the second group may include a second temperature sensor for sensing the temperature of the second group. This can improve the responsiveness of the temperature sensor to changes in the group temperature. Therefore, compared with, for example, a heater assembly including only a single temperature sensor, the fault detection responsiveness of the heater assembly can be improved. Specifically, debris entering the heater assembly may cause blockage of the airflow path, which may cause local overheating of the resistor bar and / or a single point failure of the electrical components used to control the resistor bar. By providing a dedicated temperature sensor for each group, each temperature sensor can be located closer to the possible location of the blockage, thereby responding faster when a blockage occurs. This increased response time can lead to improved fault detection responsiveness, which can improve the safety of the heater assembly. In addition, the temperature sensor can better respond to group temperature changes that are not related to the fault (for example, if the group temperature is maintained at the set point temperature), which can lead to improved temperature control accuracy for each group.

[0025] The heater assembly may include a controller for controlling the power supply to each group based on the temperature sensed by the corresponding temperature sensor of each group. Thus, the granularity of control over heating within the heater assembly may be improved. In addition, the safety of the heater assembly may also be improved because, for example, the controller may cut off the power supply to the group if the corresponding sensed temperature exceeds a safe operating threshold temperature.

[0026] The first and second groups may each include only one temperature sensor. A single temperature sensor per group may provide a good balance between the competing demands of increasing the responsiveness of the heater assembly and reducing costs and the airflow obstruction caused by additional temperature sensors.

[0027] The first temperature sensor may be located within the airflow path. As a result, the first temperature sensor may be more responsive to a blockage in the airflow path than, for example, a temperature sensor not located in the airflow path. The second temperature sensor may be located within the airflow path.

[0028] The first temperature sensor may be located between two of the first plurality of resistive strips of the first group. Thus, when there is no airflow (e.g. due to blockage), the first temperature sensor is heated from both sides, which may improve the responsiveness of the first temperature sensor, e.g. due to natural convection in different orientations. The second temperature sensor may be located between two of the second plurality of resistive strips of the second group.

[0029] The first group may include at least three resistor bars, and a greater number of the resistor bars of the first group may be located upstream of the first temperature sensor compared to resistor bars located downstream of the first temperature sensor. Due to airflow through the heater assembly, the temperature sensor may be more able to sense the temperature of the resistor bars located upstream of the temperature sensor than the resistor bars located downstream of the temperature sensor. Therefore, by positioning more resistor bars upstream of the temperature sensor, the temperature sensor may be able to detect overheating of a greater number of resistor bars than if a greater number of resistor bars were located downstream of the temperature sensor. Therefore, the fault detection responsiveness of the hair care appliance may be improved.

[0030] The second group may include at least three resistor bars, and a greater number of the resistor bars of the second group may be located upstream of the second temperature sensor than resistor bars located downstream of the second temperature sensor.

[0031] The first frame may include an outer wall portion and an inner wall portion. The outer wall portion may be further away from the center of curvature of the curved path than the inner wall portion. The first temperature sensor may be positioned so that the distance between the outer wall portion and the first temperature sensor is less than the distance between the inner wall portion and the first temperature sensor. Since the airflow follows the curved path, the momentum of the debris passing through the heater assembly may cause the debris to accumulate primarily on the outer wall portion. Therefore, by positioning the first temperature sensor relatively close to the outer wall portion, the fault detection responsiveness of the first temperature sensor may be improved.

[0032] The second frame may include an outer wall portion and an inner wall portion. The outer wall portion of the second frame may be further away from the center of curvature of the curved path than the inner wall portion of the second frame. The second temperature sensor may be positioned such that a distance between the outer wall portion of the second frame and the second temperature sensor is less than a distance between the inner wall portion of the second frame and the second temperature sensor.

[0033] The distance between the outer wall portion of the first frame and the first temperature sensor may be no less than 14% of the distance between the outer wall portion of the first frame and the inner wall portion of the first frame. As a result, the first temperature sensor may be located relatively close to the center point of the hole of the first frame. Being located relatively close to the center point of the hole may result in improved responsiveness of the first temperature sensor to a first set of temperature changes that are not related to a fault. Specifically, when the temperature of the first group changes, the center of the airflow passing through the center point of the hole may change faster than the airflow portion away from the center point.

[0034] A distance between the outer wall portion of the second frame and the second temperature sensor may be not less than 14% of a distance between the outer wall portion of the second frame and the inner wall portion of the second frame.

[0035] The distance between the outer wall portion of the first frame and the first temperature sensor may be no greater than 31% of the distance between the outer wall portion of the first frame and the inner wall portion of the first frame. Being located relatively close to the outer wall may reduce the obstruction of the airflow by the first temperature sensor. In addition, in examples where a portion of the first resistor bar has a curved profile, being located relatively close to the outer wall may reduce the likelihood that the first temperature sensor contacts the segments of the first resistor bar when the segments are deflected. This may improve the safety of the heater assembly by reducing the likelihood that the first temperature sensor shorts to the first resistor bar.

[0036] A distance between the outer wall portion of the second frame and the second temperature sensor may be no greater than 31% of a distance between the outer wall portion of the second frame and the inner wall portion of the second frame.

[0037] The first resistor bar may include a plurality of parallel straight segments and a plurality of curved segments. Each curved segment may connect one of the straight segments to an adjacent straight segment. This shape of the resistor bar may enable the first resistor bar to be relatively strong during dynamic loads (e.g., if the heater assembly falls).

[0038] The second resistor strip may include a plurality of parallel straight segments and a plurality of curved segments, wherein each curved segment may connect one of the straight segments to an adjacent straight segment.

[0039] The first resistor bar may include a first section and a second section, and the cross-section of the first section may be different from the cross-section of the second section. As a result, the function of the first resistor bar may be improved. For example, the area of ​​each cross-section may be different, which may cause the heat provided by the resistor bar to the airflow (proportional to the area of ​​each cross-section) to vary on the first resistor bar. In another example, the shape of each cross-section may be different, which may enable the airflow to be manipulated differently at different locations on the first resistor bar. Such different airflow manipulations may be used, for example, to produce a more uniform and / or more average airflow.

[0040] The second resistor strip may include a first segment and a second segment, and a cross-section of the first segment may be different from a cross-section of the second segment.

[0041] The heater assembly may include a housing, and the housing may include a first portion and a second portion that are attached to each other such that the first and second frames are located within the housing. Such a "clamshell" housing may enable the heater assembly to be relatively simple to assemble. Furthermore, the housing may be relatively simple to seal, thereby reducing the likelihood that the airflow will deviate from the intended airflow path.

[0042] The first portion of the housing and the second portion of the housing may include a plurality of recesses, and each recess may be used to receive one of the first frame and the second frame. As a result, assembly of the heater assembly may be simplified because the frames may be held by the recesses rather than additional fasteners or additional manufacturing steps, such as an adhesive application step.

[0043] The heater assembly may include a spacer that spaces the first frame from the second frame along a curved path, and a clamp that applies a compressive force to secure the first frame and the second frame to the spacer. As a result, the components of the heater assembly may be held in place relative to each other.

[0044] The first frame may include a hole defining an airflow path, a first side facing the airflow path, and a second side facing away from the airflow path. The first resistor bar may include a conductive fin extending from the first side through the first frame to the second side. As a result, the first resistor bar may be connected to a cable or a conductive strip for providing power to the first resistor bar outside the airflow path. Therefore, the airflow path may not be obstructed by the cable or the conductive strip.

[0045] The second frame may include a hole defining an airflow path, a first side facing the airflow path, and a second side facing away from the airflow path.The second resistor strip may include a conductive tab extending from the first side through the second frame to the second side.

[0046] According to a second aspect of the present invention there is provided a hair care appliance comprising a heater assembly according to the first aspect of the present invention.

[0047] According to a third aspect of the invention, there is provided a heater assembly for a hair care appliance, the heater assembly comprising a frame and a resistor bar. The frame comprises an aperture, an upstream face and a downstream face defining an airflow path. The resistor bar is supported by the frame so that the resistor bar is held within the airflow path. A plane extends between and perpendicular to the upstream face and the downstream face and extends through a center point of the aperture. A portion of the resistor bar is shaped so that when viewed in the plane, the portion of the resistor bar has a curved profile and the portion has a radius of curvature of no greater than 45 mm.

[0048] In use, the resistor bar may deflect due to airflow forces on the resistor bar and temperature changes of the resistor bar. This deflection may cause the resistor bar to contact adjacent components of the heater assembly, which may cause the heater assembly to malfunction. Therefore, by having a curved profile, the deflection can be controlled by shaping the resistor bar so that the resistor bar deflects in a known direction. This deflection control can improve the reliability and safety of the heater assembly by reducing the possibility of the resistor bar contacting adjacent components. Having a radius of curvature of no more than 45 mm can provide sufficient deflection direction control for the resistor bar to be positioned relatively close to other components, such as other resistor bars of the heater assembly, which can improve the compactness of the heater assembly compared to a heater assembly having a resistor bar including a larger radius of curvature.

[0049] The heater assembly according to the third aspect may include: a second frame, which includes a hole defining an airflow path; and a second resistor bar, which is supported by the second frame so that the second resistor bar is maintained in the airflow path, wherein the frame and the second frame are arranged along a curved path. Arranging the frame along the curved path, and thereby arranging the resistor bar, can enable a hair care appliance incorporating the heater assembly to have a good ergonomic arrangement and a relatively compact arrangement. Specifically, it is ergonomically advantageous that the hair care appliance includes an inlet and a handle in which a relatively heavy component (such as an airflow generator) is located, and includes a curved portion of a rotating airflow path so that the airflow enters via the inlet and is discharged from the outlet in a direction orthogonal to the longitudinal axis of the handle. By arranging the frame and the resistor bar along the curved path, the heater assembly can be located in the curved portion, thereby providing a relatively compact and ergonomic arrangement.

[0050] Providing two resistor bars can enable greater flexibility in the design of the heater assembly, which can improve the functionality of the heater assembly. For example, each resistor bar can have a different geometry, so that the geometry of each resistor bar can be tailored to a specific airflow pattern at a different point along the tortuous path. In another example, the geometry of each resistor bar can be modified so that each resistor bar operates at a different temperature, which can reduce the likelihood of the resistor bar overheating and failure.

[0051] Furthermore, having two resistor bars and two associated frames may enable each frame and resistor bar to be formed separately and positioned independently along a curved path. This may make the heater assembly easier to manufacture than, for example, an integral curved frame and integral resistor bar.

[0052] According to a fourth aspect of the present invention, there is provided a heater assembly for a hair care appliance, the heater assembly comprising a first group of resistor bars and a second group of resistor bars. The first group of resistor bars and the second group of resistor bars define an airflow path. The first group of resistor bars comprises a first plurality of resistor bars held within the airflow path, and a first temperature sensor for sensing the temperature of the first group of resistor bars. The second group of resistor bars comprises a second plurality of resistor bars held within the airflow path, and a second temperature sensor for sensing the temperature of the second group of resistor bars. The first plurality of resistor bars are electrically connected in series with each other, and the second plurality of resistor bars are electrically connected in series with each other.

[0053] Providing a dedicated temperature sensor for each group can improve the responsiveness of the temperature sensor to changes in the group temperature. Therefore, the fault detection responsiveness of the heater assembly can be improved compared to, for example, a heater assembly in which the heater assembly only includes a single temperature sensor. Specifically, debris entering the heater assembly may cause blockage of the airflow path, which may cause local overheating of the resistor bar. By providing a dedicated temperature sensor for each group, each temperature sensor can be located closer to the possible location of the blockage, thereby responding faster when a blockage occurs. This increased response time can result in improved fault detection responsiveness, which can improve the safety of the heater assembly. In addition, the temperature sensor can better respond to group temperature changes that are not related to faults (for example, if the group temperature is maintained at the set point temperature), which can lead to improved temperature control accuracy for each group.

[0054] Arranging the resistor bars into groups and connecting the resistor bars within the groups in series can reduce the amount of wiring in the heater assembly and simplify the wiring compared to an arrangement of individual resistor bars connected in parallel. This can reduce costs and improve the manufacturability of the heater assembly.

[0055] Providing multiple resistor bars can enable greater flexibility in the design of the heater assembly, which can improve the functionality of the heater assembly. For example, each resistor bar can have a different geometry, so that the geometry of each resistor bar can be tailored to a specific airflow pattern at a different point along the airflow path. In another example, the geometry of each resistor bar can be modified so that each resistor bar operates at a different temperature, which can reduce the likelihood of the resistor bar overheating and failure.

[0056] Where appropriate, optional features of the first resistor strip or the second resistor strip of the first aspect of the invention may be equally applicable to resistor strips in both the first plurality of resistor strips and the second plurality of resistor strips.

[0057] The first group may comprise a first plurality of frames and the second group may comprise a second plurality of frames. Where appropriate, optional features of the first frame or second frame of the first aspect of the invention may apply equally to frames in the first and second plurality of frames.

[0058] The first group and the second group may be arranged along a curved path. Arranging the groups along the curved path may enable a hair care appliance incorporating a heater assembly to have a good ergonomic arrangement and a relatively compact arrangement. Specifically, it is ergonomically advantageous for the hair care appliance to include an inlet and a handle in which a relatively heavy component (e.g., an airflow generator) is located, and to include a curved portion of a rotating airflow path such that airflow enters via the inlet and is discharged from the outlet in a direction orthogonal to the longitudinal axis of the handle. By arranging the groups along the curved path, the heater assembly may be located within the curved portion, thereby providing a relatively compact and ergonomic arrangement.

[0059] Furthermore, having multiple resistor bars and multiple associated frames may allow each frame and resistor bar to be formed separately and positioned independently along a tortuous path. This may make the heater assembly easier to manufacture than, for example, an integral tortuous frame and integral resistor bar.

[0060] Where appropriate, optional features of various aspects of the invention may be equally applicable to other aspects of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 is a schematic diagram of a hair care appliance according to the present invention;

[0062] Figure 2 yes Figure 1 a view of a heater assembly of a hair care appliance;

[0063] Figure 3 yes Figure 2 A view of a heater assembly showing additional components;

[0064] Figure 4 yes Figure 3 A cross-sectional view of a heater assembly;

[0065] Figure 5 yes Figure 2 An exploded view of a resistor strip group of a heater assembly;

[0066] Figure 6 yes Figure 5 A view of a resistor bar support frame of a resistor bar group;

[0067] Figure 7 yes Figure 5 A view of a temperature sensor support frame of a resistor strip group;

[0068] Figure 8 yes Figure 5 An exploded view of the resistor strip group;

[0069] Fig. 9 It passes through Figure 6A cross-sectional view of a group of resistor bars and a resistor bar support frame;

[0070] Fig.10 yes Figure 2 a view of a spacer of a heater assembly;

[0071] Fig.11 yes Figure 2 a view of a fixture for a heater assembly;

[0072] Fig.12 yes Figure 2 a block diagram of the electrical components of the heater assembly;

[0073] Fig.13 is a view of the replacement resistor strip;

[0074] Fig.14 is a view of an alternative heater assembly; and

[0075] Fig.15 yes Fig.14 A cross-sectional view of a portion of a housing of an alternative heater assembly. DETAILED DESCRIPTION

[0076] Figure 1 A hair care appliance 10 according to the present invention is schematically illustrated. The hair care appliance 10 comprises a body 12, an air inlet 14, an air outlet 16, an air flow generator 18, a power cable 20 and a heater assembly 22.

[0077] The body 12 includes a handle portion 24, a curved portion 26 and an outlet portion 28. The handle portion 24 is generally straight and cylindrical and is gripped by a user during use. The air inlet 14 is located at one end of the handle portion 24 and includes a plurality of holes formed in the handle portion 24. The handle portion 24 accommodates the airflow generator 18.

[0078] The curved portion 26 extends between the handle portion 24 and the outlet portion 28 and turns approximately 90° from the handle portion 26 to the outlet portion 28. The heater assembly 22 is located within the curved portion 26.

[0079] The outlet portion 28 is generally straight, cylindrical and hollow. The air outlet 16 is a generally circular hole formed at the end of the outlet portion 28.

[0080] In use, the air flow generator 18 generates an air flow from the air inlet 14 through the handle portion 24, the heater assembly 22 and the outlet portion 28 to the air outlet 16. The air flow generator 18 typically includes an impeller driven by a motor.

[0081] The power cable 20 is connected to a mains power source to provide power to other electrical components of the hair care appliance 10, such as the heater assembly 22. In other examples, the power cable 20 may be replaced by a power source including batteries that provide a DC voltage.

[0082] Now turn to Figures 2 to 4 The heater assembly includes a first group 30, a second group 32 and a third group 34; a first spacer 36 and a second spacer 38; an electrical wiring (looming) 40; a control unit 42 ( Fig.12 and a clamp 44. The heater assembly 22 defines a flow path extending between an upstream end of the heater assembly 22 and a downstream end of the heater assembly 22.

[0083] Now go to Figure 5 , each set 30, 32, 34 includes three resistor bar support frames 46, a temperature sensor support frame 47, three resistor bars 48, and a temperature sensor 50. In other examples, each set 30, 32, 34 may include a different number of frames 46, 47 and associated resistor bars 48 and temperature sensors 50.

[0084] Now go to Figure 6 , each resistor bar support frame 46 is generally annular and thus includes an aperture 54. The aperture 54 defines a portion of the flow path. Each frame 46 is shaped such that a top channel 56 is defined by the top of the frame and a bottom channel 58 is defined by the bottom of the frame. The channels 56, 58 are defined on a side of each frame 46 facing away from the aperture 54. As will be described in more detail below, each resistor bar support frame 46 supports one of the resistor bars 48.

[0085] Now go to Figure 7 , the temperature sensor support frame 47 is generally annular and thus includes a hole 55 and two support members 60. The hole 55 defines a portion of the flow path. The frame 47 is shaped so that the top channel 57 is defined by the top of the frame 47 and the bottom channel 59 is defined by the bottom of the frame 47. The channels 57, 59 are defined by the side of the frame 47 facing away from the hole 55.

[0086] The support members 60 are spaced apart from each other and extend from the top of the frame 47 into the hole 54. The temperature sensor 50 extends between the distal ends of the support members 60 so that the frame 47 supports the temperature sensor 50.

[0087] Now go to Figure 8, when the groups 30, 32, 34 are assembled, the frames 46, 47 abut each other so that the groups 30, 32, 34 have a generally tubular shape. The frames 46, 47 are arranged so that two resistor bar support frames 46 are located upstream of the temperature sensor support frame 47. The third resistor bar support frame 46 is located downstream of the temperature sensor support frame 46. Therefore, the temperature sensor 50 is located between two resistor bars 48 of the groups 30, 32, 34, and a greater number of resistor bars 48 of the groups 30, 32, 34 are located upstream of the temperature sensor 50 rather than downstream of the temperature sensor 50. In addition, the frames 46, 47 are oriented so that the top channels 56, 57 are aligned with each other and the bottom channels 58, 59 are aligned with each other.

[0088] Back to Figure 6 , each resistor bar 48 extends through the hole 54 of the corresponding resistor bar support frame 46, thereby extending through the portion of the flow path defined by the corresponding frame 46. Each resistor bar 48 includes a plurality of parallel straight segments 62, a plurality of curved segments 64, a plurality of protrusions 66, and two conductive tabs 68. The curved segment 64 is bent approximately 180 degrees and connects one of the straight segments 62 to an adjacent straight segment 62, so that the resistor bar 48 has a generally serpentine shape.

[0089] Each protruding portion 66 protrudes from one of the bent sections 64 into the corresponding frame 46, so that the resistor bar 48 is supported by the corresponding frame 46. Therefore, the resistor bar 48 is held by the corresponding frame 46 within the flow path.

[0090] Each conductive tab 68 forms an end of the resistive strip 48 and extends through the respective frame 46 from a first side of the frame 46 facing the aperture 54 (and flow path) of the respective frame 46 to a second side of the frame 46 facing away from the aperture 54 of the respective frame 46. A portion of each tab 68 extends from the second side and is connected to the electrical harness 40.

[0091] In this example, each resistor bar 48 is formed from a sheet of material by etching so that the resistor bar 48 is defined between cuts in the sheet. The airflow path is defined by the cuts in the sheet so that in use the airflow passes through the cuts. Likewise, the resistor bar 48 may be formed by other processes such as stamping.

[0092] The first plane 88 extends between the upstream and downstream faces of each resistor bar support frame 46. The first plane 88 also extends through the center point of the hole 54 of the frame 46. Fig. 9 As shown, when viewed in a first plane 88, portion 86 of resistor strip 48 has a curved profile having a radius of curvature no greater than 45 mm.

[0093] A second plane 90 extends between and perpendicular to the upstream and downstream faces of each resistor bar support frame 46. In addition, the second plane 90 extends perpendicular to the first plane 88 and extends through the center point of the hole 54 of the frame 46. The portion 86 of the resistor bar 48 is shaped so that when viewed in the second plane 90, the portion 86 of the resistor bar 48 has a curved profile with a radius of curvature no greater than 45 mm.

[0094] The resistor bar support frame 46 is arranged within each group 30, 32, 34 so that the vertex 92 of the portion 86 of each resistor bar 48 is located further downstream than the point at which the protruding portion 66 protrudes into the frame 46, i.e., the point at which the resistor bar 48 is held by the frame 46. The portion 86 is sized so that the vertex 92 is located further downstream than the downstream face of the frame 46. That is, the upper limit of the radius of curvature of the curved profile is determined by the distance (depth) between the upstream face and the downstream face of the frame 46. In addition, the vertex 92 of the portion 86 of the resistor bar 48 is centered at the center point of the hole 54 of the frame 46. In this example, only the straight segment 62 of the resistor bar 48 is part of the portion 86. However, in other examples, the portion 85 may include a greater or lesser proportion of the resistor bar 48. For example, the entire resistor bar 48 including the curved segment 64 and the protruding portion 66 may form part of the portion 86.

[0095] The temperature sensor 50 extends between the support members 60 of the temperature sensor support frame 47 so that the temperature sensor 50 is located within the aperture 55 of the frame 47 and thus within the airflow path. The temperature sensor 50 is electrically connected to wiring extending from the temperature sensor 50, through the support members 60 and connected to the electrical harness 40. The temperature sensor 50 senses the temperature of the groups 30, 32, 34.

[0096] Now go to Fig.10 , each spacer 36, 38 has a generally cylindrical tubular shape that is bent along its length. Thus, each spacer 36, 38 defines an aperture 61 that defines a portion of the airflow. Each spacer 36, 38 is shaped so that a top channel 63 is defined by the top of each spacer 36, 38 and a bottom channel 65 is defined by the bottom of each spacer 36, 38. Channels 63, 65 are defined by a side of each spacer 36, 38 that faces away from aperture 61.

[0097] Clamp 44 (such as Fig.11 1 and 2) include a lower member 74 and an upper member 76. The lower member 74 includes a body 78, an upper arm 80 and a lower arm 82. The body 78 has a generally hollow cylindrical shape. The upper arm 80 and the lower arm 82 each protrude from opposite sides of the body 78 in a generally downstream direction and have a generally curved elongated shape. Each arm includes a clip at a distal end.

[0098] The upper member 76 has a generally cylindrical tubular shape that is bent along its length. Thus, the upper member 76 defines a hole. The shape of the upper member 76 is designed so that the top of the upper member 76 defines a top channel and the bottom of the upper member 76 defines a bottom channel. The channels are defined by the side of the upper member 76 facing away from the hole of the upper member 76. Each channel includes a clip receiving feature for each clip of the arms 78, 80 of the clamp 44 to clamp.

[0099] To assemble the heater assembly 22, the downstream end of the first set 30 is abutted against the lower member 74 of the fixture 44. The first set 30 is oriented such that the upper arm 80 extends through the top channels 56, 57 and the lower arm 82 extends through the bottom channels 58, 59 of the frames 46, 47 of the first set 30. The interaction of the arms 80, 82 and the channels 56, 57, 58, 59 can help orient and secure the first set 30 to the lower member 78 of the fixture 44. The downstream end of the first spacer 36 is then abutted against the upstream end of the first set 30. In a manner similar to the first set 30, the first spacer 36 is oriented such that the upper arm 80 extends through the top channel 63 and the lower arm 82 extends through the bottom channel 65. The downstream end of the second set 32 ​​is then abutted against the upstream end of the first spacer 36. The process is then repeated for the second spacer 38 and the third set 34. The downstream end of the upper member 76 of the clamp 44 then abuts the upstream end of the third set 34 and the clips of the arms 80, 82 then clamp to the clip receiving features of the clamp upper member 76. Thus, the clamp 44 applies a compressive force to the heater assembly 22 to clamp the heater assembly 22 together.

[0100] like Figure 4 As shown, when assembled, the groups 30, 32, 34 (and the frames of the groups) are arranged along a curved path 84 so that the airflow exits the upper portion of the heater assembly 22 in a direction substantially orthogonal to the direction in which the airflow enters the lower portion of the heater assembly 22. The curved path 84 is an imaginary line extending through the center point of each hole 54, 55, 61 of the frames 46, 47 and the spacers 36, 38. In this example, the arrangement of the frames 46, 47 along the curved path 84 is provided by the shape of the spacers 36, 38, which causes the frames 46, 47 of each group 30, 32, 34 to be tilted relative to the frames 46, 47 of the other groups 30, 32, 34. However, as will be discussed below, the arrangement of the frames 46, 47 along the curved path 84 can be provided by means other than the spacers 36, 38. In this example, the portion of the flow path defined by each individual group 30, 32, 34 or spacer 30, 32 can be straight. Thus, in this example, the curved path 84 is formed by a plurality of straight portions that are inclined with respect to one another to form the overall curved path 84 .

[0101] Arranging the frames 46, 47 and the resistive strip 48 along the curved path 84 can enable both good ergonomics and a relatively compact arrangement of the hair care appliance 10 incorporating the heater assembly 22. Specifically, it may be ergonomically advantageous for the hair care appliance 10 to include an inlet 14 and a handle 24 in which relatively heavy components (e.g., the airflow generator 18) are located, and to include a curved portion 26 that rotates the airflow path so that airflow enters through the inlet 14 and exits from the outlet 16 in a direction perpendicular to the longitudinal axis of the handle 24. By arranging the frames 46, 47, and thus the resistive strip 48, along the curved path 84, the heater assembly 22 can be located within the curved portion 26, thereby providing a relatively compact and ergonomic arrangement.

[0102] Providing multiple resistor bars 48 may enable greater flexibility in the design of the heater assembly 22, which may improve the functionality of the heater assembly 22. For example, each resistor bar 48 may have a different geometry, such that the geometry of each resistor bar 48 may be tailored to a particular airflow pattern at a different point along the tortuous path 84. In another example, the geometry of each resistor bar 48 may be modified so that each resistor bar 48 operates at a different temperature, which may reduce the likelihood of the resistor bar 48 overheating and failing.

[0103] Additionally, having multiple resistor bars 48 and multiple associated frames 46 may allow each frame 46 and resistor bar 48 to be separately formed and independently positioned along the curved path 84. This may make the heater assembly 22 easier to manufacture than, for example, a unitary curved frame and unitary resistor bar.

[0104] Now turn to Fig.12 The control unit 42 includes a set of switches 70 and a controller 72 .

[0105] Each switch 70 is connected between the power cable 20 and one of the groups 30, 32, 34 through the wiring harness 40. Therefore, when one of the switches 70 is closed, power is supplied to the relevant group 30, 32, 34. Conversely, when the switch 70 is open, power supply to the group 30, 32, 34 is stopped.

[0106] The controller 72 is connected to the airflow generator 18 and the switch 70. In addition, the controller 72 is connected to the temperature sensor 50. As a result, the sensed temperature of each group 30, 32, 34 is provided to the controller 72. The controller 72 is responsible for controlling the operation of the hair care appliance 10. In particular, the controller 72 controls the opening and closing of the switch 70 in response to the sensed temperature of each group 30, 32, 34 provided by the temperature sensor 50, thereby controlling the power supplied to the group 30, 32, 34. For example, the controller 72 can control the switch 70 so that the temperature of each group 30, 32, 34 sensed by the corresponding temperature sensor 50 is maintained at a specific set point. In addition, if the sensed temperature of the group 30, 32, 34 exceeds a safe operating threshold, the controller 72 can open one of the switches 70 to stop the power supply to the group 30, 32, 34. The controller 72 also controls the operation of the airflow generator 18.

[0107] In use, the airflow generated by the airflow generator 18 enters the heater assembly 22 at the downstream end of the lower portion 78 of the clamp 44 and then exits at the upstream end of the upper portion 76 of the clamp 44 along the airflow path through the heater assembly 22. During normal operation of the heater assembly, the switch 70 is closed and power is provided to the groups 30, 32, 34. Therefore, as the airflow passes through the heater assembly 22, the resistive strip 48 heats the airflow. During operation, debris may accumulate inside the heater assembly 22. This debris may form an obstruction to the airflow, which may cause the temperature of one of the groups 30, 32, 34 to increase excessively. In this case, the controller 72 will detect a fault caused by the sensed temperature of the group 30, 32, 34 exceeding the safe operating threshold, and the controller 72 will then open the relevant switch 70 to stop powering the group 30, 32, 34.

[0108] Due to the arrangement of the heater assembly 22, the top of each temperature sensor support frame 47 is farther from the center of curvature of the curved path 84 than the bottom of each frame 47. Therefore, it can be said that each temperature sensor support frame 47 includes an outer wall portion (the top of the frame 47) and an inner wall portion (the bottom of the frame 47). The height of the support member 60 of the support frame 47 is such that the distance between the outer wall portion and the temperature sensor 50 is 20% of the distance between the outer wall portion and the inner wall portion (i.e., the width of the hole 54 of the frame 46, 47). Likewise, in other examples, the height of the support member 60 can be designed to use other distances.

[0109] The airflow distribution across the width of the aperture 54 of each frame 46 may be different. For example, the velocity of the airflow may vary across the width of the aperture 54. To compensate for this difference, different segments of each resistor strip 48 may have different cross-sections. For example, Fig.13An alternative resistor track 73 is shown in which the cross-sectional area and geometry of the segment of the resistor track 73 located at the center point of each aperture 54 is different than the segment located further from the center point of the aperture 54 .

[0110] The portion of the curved path 84 extending between the center point of the aperture 54 of the most downstream frame 46, 47 and the center point of the aperture 54 of the most upstream frame 46, 47 subtends a central angle of approximately 80 degrees. In other examples, the portion of the curved path 84 may subtend other angles.

[0111] In the above example, the arrangement of the frames 46, 47 along the curved path 84 is provided by the shape of the spacers 36, 38, which causes the frames 46, 47 of each group 30, 32, 34 to be tilted relative to the frames 46, 47 of the other groups 30, 32, 34. However, the arrangement of the frames 46, 47 along the curved path 84 can be provided by means other than the spacers 36, 38. For example, Fig.14 and 15 An alternative heater assembly 100 is shown.

[0112] The alternative heater assembly 100 is identical to the heater assembly 22 described above, with the following exceptions. First, the spacers 36, 38 are omitted. Second, the clamp 44 is replaced by a housing 102. The housing 102 includes a first portion 104 and a second portion 106.

[0113] Now turn to Fig.15 , each portion of the housing 104, 106 includes a main body 108, a plurality of recesses 110, 112, and a mating interface 114. The main body 108 has a C-shaped cross-section and is bent approximately 90 degrees along its length. Each recess 110, 112 is located on the concave side of the main body 108. Each of the three recesses 110 is sized to receive half of one of the groups 30, 32, 34, and is positioned relative to each other so that when the groups 30, 32, 34 are inserted into the recesses, the groups 30, 32, 34 are arranged along the curved path 84. The fourth recess 112 is sized to receive the electrical wiring 40. The mating interface 114 is provided along the end of the C-shaped cross-section and docks with a corresponding interface on the second portion 106 of the housing 102 to attach the portions 104, 106 together.

[0114] To assemble the alternative heating assembly 100, each group 30, 32, 34 is placed in one of the recesses 110, and the two parts 104, 106 of the housing 102 are brought together so that the mating interface 114 is butted to attach the first part 104 to the second part 106 and hold the groups 30, 32, 34 in place. When assembled, the housing 102 has a generally cylindrical tubular shape that is bent about 90 degrees along its length. A seal is also provided along the juncture between the first part 104 and the second part 106.

[0115] While specific examples and embodiments have been described thus far, it should be understood that these are illustrative only and that various modifications may be made without departing from the scope of the invention as defined by the claims.

Claims

1. A heater assembly for a hair care appliance, the heater assembly comprising: a first frame and a second frame arranged along a curved path to define an airflow path; a first resistor bar supported by the first frame such that the first resistor bar is retained within the airflow path; and The second resistor bar is supported by the second frame so that the second resistor bar is maintained within the airflow path.

2. The heater assembly of claim 1, wherein: The first frame is spaced apart from the second frame along the curved path.

3. The heater assembly of claim 2, wherein: The first frame is spaced apart from the second frame by a spacer.

4. The heater assembly of claim 3, wherein: The spacer defines a portion of the airflow path.

5. A heater assembly as claimed in any preceding claim, wherein: The first frame and the second frame each include an aperture defining the airflow path; The curved path extends through a center point of each aperture; and The portion of the curved path extending between the center point of each aperture subtends a central angle of no greater than 100 degrees.

6. A heater assembly as claimed in any preceding claim, wherein: The first frame and the second frame each include an aperture defining the airflow path; The first frame includes an upstream face and a downstream face; First plane: extending between and perpendicular to the upstream face and the downstream face; as well as a center point of the hole extending through the first frame; and A portion of the first resistor track is shaped such that, when viewed in a first plane, the portion of the first resistor track has a curved profile having a radius of curvature no greater than 45 mm.

7. The heater assembly of claim 6, wherein: Second plane: extending between and perpendicular to the upstream and downstream faces; extending perpendicular to the first plane; as well as a center point of an aperture extending through said first frame; and The portion of the first resistor track is shaped such that the portion of the first resistor track has a curved profile when viewed in a second plane.

8. A heater assembly as claimed in claim 6 or 7, wherein: The apex of the portion of the first resistor strip is located no further downstream than the downstream face; and The vertex of the portion of the first resistor strip is located no further upstream than the upstream face.

9. The heater assembly according to any one of claims 6 to 8, wherein: The apex of the portion of the first resistor strip is located further downstream than the point at which the first resistor strip is held by the first frame.

10. The heater assembly according to any one of claims 6 to 9, wherein: The apex of the portion of the first resistor strip is centered at a center point of the hole of the first frame.

11. A heater assembly as claimed in any preceding claim, wherein: The heater assembly includes a first group and a second group; A first group includes a first plurality of resistor bars including the first resistor bar, and a second group includes a second plurality of resistor bars including the second resistor bar; and The first plurality of resistor strips are electrically connected in series with each other, and the second plurality of resistor strips are electrically connected in series with each other.

12. The heater assembly of claim 11, wherein: The first group includes a first temperature sensor for sensing a temperature of the first group; and The second group includes a second temperature sensor for sensing a temperature of the second group.

13. The heater assembly of claim 12, wherein: The first temperature sensor is located within the air flow path.

14. The heater assembly of claim 13, wherein: The first temperature sensor is located between two of the first plurality of resistive strips of the first set.

15. The heater assembly of claim 14, wherein: The first group includes at least three resistor strips; and A greater number of the resistive bars of the first set may be located upstream of the first temperature sensor than the resistive bars located downstream of the first temperature sensor.

16. The heater assembly of any one of claims 13 to 15, wherein: The first frame includes an outer wall portion and an inner wall portion; the outer wall portion being located further from a center of curvature of the curved path than the inner wall portion; The first temperature sensor is positioned such that a distance between the outer wall portion and the first temperature sensor is smaller than a distance between the inner wall portion and the first temperature sensor.

17. The heater assembly of claim 16, wherein: The distance between the outer wall portion and the first temperature sensor is not less than 14% of the distance between the outer wall portion and the inner wall portion.

18. A heater assembly as claimed in claim 16 or 17, wherein: The distance between the outer wall portion and the first temperature sensor is no greater than 31% of the distance between the outer wall portion and the inner wall portion.

19. A heater assembly as claimed in any preceding claim, wherein: The first resistor strip comprises: multiple parallel straight line segments; and Multiple curved segments, each connecting one of the straight segments to an adjacent straight segment.

20. A heater assembly as claimed in any preceding claim, wherein: The first resistor strip comprises a first segment and a second segment; and The cross-section of the first section is different from the cross-section of the second section.

21. A heater assembly as claimed in any preceding claim, wherein: The heater assembly includes a housing; and The housing includes a first portion and a second portion that are attached to each other such that the first frame and the second frame are located within the housing.

22. A heater assembly as claimed in any preceding claim, wherein: The heater assembly comprises: a spacer that spaces the first frame apart from the second frame along the curved path; and A clamp applies a compressive force to secure the first frame and the second frame to the spacer.

23. A heater assembly as claimed in any preceding claim, wherein: The first framework includes: an aperture defining the airflow path; a first side facing the airflow path; and a second side facing away from the airflow path; and The first resistor bar includes a conductive tab extending through the first frame from a first side to a second side.

24. A hair care appliance comprising a heater assembly as claimed in any preceding claim.

Images